Write down the condition for thin film interference. Calculatethe position (angular) and the distance between the 3rd and 4thdark lines of the interference pattern on the screen when the slitsare spaced 0.450 mm apart and are placed 80.0 cm from the screen.The slits are illuminated with coherent light of wavelength 550nm.Also calculate the distance between the 3rd and 4th dark lines whenthe entire apparatus was immersed in water. How this separationcompares with separation in air and why? (nwater = 1.333)
